Dogwood - if the deer were somewhere where there was a lot of snow, then it would be better off than here (again, in the scenario where there are natural predators) but I honestly don't think it would have lasted that long here if there was something other than humans to hunt it; it would stick out like a sore thumb! On an animal with no thumbs. If it did survive, it would be dumb luck! IMO of course.
Pete, I don't dispute that this deer *might* be less able to survive in a natural (predator rich) environment. But part of the point of recessive traits in the gene pool is to keep them around in case they prove to be valuable later.
In other words if this same species of deer were to migrate northerly (assuming you weren't an island, of course) then the recessive white deers would suddenly be more successful than their brown peers and slowly the white would dominate. Recessive traits are natures way of saying "just in case we need it later..."
You don't want to remove that potential from the pool by artificial (hunting) means.
That's why I feel hunting for specific genetic traits isn't ethical. Hunt the ordinary and let the extraordinary survive to enrich the pool.
All of that said, I concede that you could make a case here that after a few breeding seasons it would be wise to harvest the white deer because -- without natural predators -- having it flourish would artificially encourage the trait as successful.
That's the conundrum we get into once we've knocked things too far out of balance.
Wait!!!!
Here's the better solution. Let the white deer live and reintroduce WOLVES to the UK and let the wolves sort it out as they should! Wouldn't you love to see some wolves in the countryside...
Then we'd all be happy